Nutritional status plays an important role in the incidence of postoperative complications and the prognosis of various tumours. The prognostic value of preoperative nutritional factors in patients with pancreatic cancer is not known. This retrospective study included 268 patients who underwent resection for adenocarcinoma of the pancreas. The predictive value of preoperative nutritional status for postoperative outcome (survival, complications) was assessed. Nutritional factors included the three constitutional indices, serum albumin and Onodera's prognostic nutrition index (PNI), calculated as 10 × serum albumin (g/dl) + 0·005× total lymphocyte count (per mm(3)). In multivariable analysis preoperative low PNI (but not low albumin) was an independent prognostic factor for poor survival: hazard ratio (HR) 1·73 (95 per cent confidence interval (c.i.) 1·21 to 2·47). The accuracy of a PNI value of less than 45 as cut-off for clinically significant preoperative malnutrition in predicting 1- or 2-year survival after surgery was, however, limited (66·4 and 56·3 per cent respectively). Low preoperative albumin concentration and PNI were significantly associated with postoperative complications: odds ratio 1·98 (95 per cent c.i. 1·18 to 3·32) and 2·14 (1·23 to 3·73) respectively. Low PNI and low body mass index were independently associated with pancreatic fistula: HR 2·52 (1·37 to 4·63) and 0·40 (0·17 to 0·93) respectively. The PNI is associated with overall survival and postoperative complications, in particular pancreatic fistula, in patients with pancreatic cancer. The moderate accuracy of PNI as a predictor of survival limits its clinical use.